The aim of the proposed research is to investigate the communication behavior of school-age deaf children and to evaluate their development of communication skills. The studies are designed to shed light on the nature of the natue of the language deficit that is said to be associated with deafness and with the developmental lag that is typically observed in deaf children's acquisition of linguistic and social skills. Training studies are proposed in referential communication. Training effects will be evaluated as a function of age, amount of practice or training, and task difficulty. An attempt will be made to identify the cognitive, linguistic, and social competencies required for successful performances. Specific grammatical features of American Sign Language will be identified so that their acquisition can be studied developmentally.